There are many types of latch systems for enclosures of devices, such as electronic devices. One well-known type of latch system is based upon an arrangement of cantilevered snaps and mating recesses. Such latch systems are advantageous in that they eliminate screws and screw bosses, thereby reducing assembly labor and increasing circuit board area usable for the electronic device. A further advantage is that such latch systems discourage unauthorized tampering with the electronic device by users who cannot readily discern a method of opening the enclosure.
A disadvantage of conventional latch systems using cantilevered snaps and mating recesses is that once such systems are latched together, they cannot be unlatched easily when required, e.g., for service. Simply applying force against such a conventional latch system in an attempt to unlatch it can damage or destroy the latch system. The correct--but tedious--way to unlatch such conventional systems is by prying each snap out of its mating recess using a screwdriver blade or in some cases a special enclosure disassembly tool. Still, service personnel and equipment users can and do sometimes attempt to open conventional latch systems using improper procedures resulting in damage to the latch system.
Thus, what is needed is a latch system that provides all the advantages offered by conventional latch systems using cantilevered snaps and mating recesses but that eliminates the aforementioned disadvantage. That is to say, a latch system using cantilevered snaps and mating recesses that can be both latched and unlatched without requiring the use of a tool is needed.
One aspect of the present invention is a latch member for use in a latch system of an enclosure, the latch member comprising first and second structures comprising a flexible extension member having an attachment end and a free end, the attachment end connected to the first structure in a manner that extends the free end towards the second structure. The latch member further comprises a latch tooth contiguous with the free end of the flexible extension member and having a bearing surface for engaging with a mating recess formed in the second structure. The bearing surface tapers from a substantially flat surface at a first side of the latch tooth to a substantially cylindrical surface at a second side of the latch tooth opposite the first side. When the latch tooth is inside the mating recess, the substantially flat surface engages with the mating recess, thereby latching the first and second structures together. In response to a directional unlatching force of sufficient magnitude to flex the flexible member, the substantially cylindrical surface makes contact with the mating recess in a manner that forces the latch tooth from the mating recess, thereby unlatching the first and second structures.
Another aspect of the present invention is an enclosure latch system for latching and unlatching first and second enclosure sections. The enclosure latch system comprises at least one insertable member connected to the first enclosure section, and at least one mating recess formed within the second enclosure section for engaging with the at least one insertable member, thereby latching the first and second enclosure sections together. The at least one insertable member comprises an extender member connected at an attachment end to the first enclosure section for extending the insertable member into the second enclosure section, and a latch tooth protruding from the extender member near a free end opposite the attachment end of the extender member for latching and unlatching the first and second enclosure sections. The latch tooth comprises a mating surface that tapers from substantially flat on a first side of the latch tooth to substantially cylindrical on a second side of the latch tooth opposite the first side for latching the first and second enclosure sections when the latch tooth is in the mating recess. The mating surface functions further for unlatching the first and second enclosure sections by forcibly removing the latch tooth from the mating recess in response to a directional torque resulting from a separating force applied at a first end of the first and second enclosure sections closer to the second side of the latch tooth than to the first side of the latch tooth. The enclosure latch system further comprises hinge means for rotatably engaging the first and second enclosure sections to one another at a second end opposite the first end for facilitating latching of the enclosure latch system and for preventing the application of a torque having a direction which could damage the enclosure latch system.
Another aspect of the present invention is a selective call receiver comprising a printed circuit board including selective call receiver circuits for receiving selective call messages and presenting the selective call messages to a user, and an enclosure surrounding and protecting the printed circuit board. The enclosure comprises first and second enclosure sections, and an enclosure latch system for latching and unlatching the first and second enclosure sections. The enclosure latch system comprises at least one insertable member coupled to the first enclosure section, and at least one portion of the second enclosure section forming a mating recess therein for engaging with the at least one insertable member to latch the first and second enclosure sections together. The at least one insertable member comprises a cantilever having a first end connected to the first enclosure section, and having a second end, for extending the insertable member into the second enclosure section, and a boss contiguous with the second end of the cantilever for latching and unlatching the first and second enclosure sections. The boss comprises a substantially flat surface at a first side of the boss, the flat surface tapering substantially to a point at a second side of the boss opposite the first side, for engaging with the mating recess, thereby latching the first and second enclosure sections together. The boss further comprises a substantially cylindrical surface, contiguous with and alongside the flat surface and tapering from subtending an arc of substantially 90 degrees at the second side of the boss to substantially 0 degrees at the first side. The substantially cylindrical surface is for forcibly removing the boss from the mating recess to unlatch the first and second enclosure sections in response to a directional torque resulting from a separating force applied at a first end of the first and second enclosure sections closer to the second side of the boss than to the first side. The enclosure latch system further comprises hinge means for rotatably engaging the first and second enclosure sections with one another at a second end opposite the first end for facilitating latching of the latch system and for preventing the application of a torque having a direction that could damage the enclosure latch system.